Dubbed "Mr. Nasty" during his Idol days, Cowell, 52, toldBarbara Walters on the TV titan's annual 10 Most Fascinating People special Wednesday that he couldn't go through with bedding her because he was afraid of the aftermath.

"I mean, the truth was, on the first two seasons, we couldn't travel on the same plane together. We really disliked each other that much," Cowell told Walters, arguing that they clashed due to "sexual tension…on her part."

Though she denied Cowell's claim that the pair went on a Beverly Hills dinner date when she was eight months pregnant, Denise Richards once called the X Factor judge -- engaged to makeup artist Mezhgan Hussainy -- "a hot piece of ass."